feat: creatable select

src/Select.tsx

@@ -2,6 +2,7 @@ import * as React from 'react';
 import { ReactEventHandler } from 'react';
 import ReactSelect from 'react-select';
 import ReactAsyncSelect, { Props as AsyncProps } from 'react-select/lib/Async'; // we can live with it, as it adds very little overhead (just a wrapper around Select)
+import ReactCreatableSelect, { Props as CreatableProps } from 'react-select/lib/Creatable';
 import { Props } from 'react-select/lib/Select';
 
 import { Omit } from '@stoplight/types';
@@ -35,13 +36,17 @@ export interface ISelectBaseProps {
 
 export interface ISelectProps
   extends ISelectBaseProps,
-    Omit<Omit<Props<ISelectOption>, 'noOptionsMessage'>, 'loadingMessage'> {} // pipe doesn't work for some reason
+    Omit<Props<ISelectOption>, 'noOptionsMessage' | 'loadingMessage'> {}
 
 export interface ISelectAsyncProps
   extends ISelectBaseProps,
-    Omit<Omit<AsyncProps<ISelectOption>, 'noOptionsMessage'>, 'loadingMessage'> {} // pipe doesn't work for some reason
+    Omit<AsyncProps<ISelectOption>, 'noOptionsMessage' | 'loadingMessage'> {}
 
-export type ISelect = ISelectProps | ISelectAsyncProps;
+export interface ISelectCreatableProps
+  extends ISelectBaseProps,
+    Omit<CreatableProps<ISelectOption>, 'noOptionsMessage' | 'loadingMessage'> {}
+
+export type ISelect = ISelectProps | ISelectAsyncProps | ISelectCreatableProps;
 
 export interface ISelectOption {
   label: string;
@@ -97,10 +102,14 @@ export const Select: React.FunctionComponent<ISelect> = props => {
     styles: customStyles(),
   };
 
-  if ('loadOptions' in props || 'defaultOptions' in props) {
+  if ('loadOptions' in props) {
     return <ReactAsyncSelect {...actualProps} />;
   }
 
+  if ('onCreateOption' in props) {
+    return <ReactCreatableSelect {...actualProps} />;
+  }
+
   return <ReactSelect {...actualProps} />;
 };